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Use the interactive map below to check population changes. Zoom in to see where Podocnemis unilfilis is Endangered based on IUCN Red List criteria - A3bd.

  • Overall Podocnemis unilfilis is Endangered based on future population size reduction criteria. The adult female population is predicted to decline by 58.3% in the future (25 and 75% quantile range: 59 - 57.6 % decline).

The analysis is developed here: https://github.com/darrennorris/TACAR, and is an extension of Norris et. al. 2019 that includes:

  • Stochastic population projections.
  • Future impacts to populations caused by human acessibility (hunting) and actions that reduce river connectivity.

Map

Due to the number of points, the map can become slow to respond when you zoom in. Zoom out to a level showing fewer points and you can pan around the map to find the area of interest. Then zoom in again to check the coloured points.

When you zoom in you will see shaded points. The points follow rivers produced by remote sensing (Free-flowing Rivers, 2019: https://doi.org/10.1038/s41586-019-1111-9). To facilitate online viewing the mapped points are a subset at intervals of approximately 10 kilometers. The points are brown where populations are predicted to decline by 50% or more within 3 generations (42 years). Brown points therefore represent rivers where the species is Endangered, following the IUCN Red List population size reduction criteria - A3bd (https://www.iucnredlist.org/about/faqs).

Summaries

A summary of the map results is presented below. This includes summaries by country and major basin using the full set of points at 1 kilometer intervals. Results include the size and extent of likely population changes. The column “population change” is the difference in the number of adult females after 3 generations (42 years). This is consistent with the population sze reduction criteria used by the IUCN Red List. The column “River length Endangered”, is the proportion of river length where populations declined by 50% or more, and represents the spatial extent of future changes.

Summary by country.

Country Population change River length Endangered (prop) River length (km)
Bolivia -0.58 (-0.58 – -0.57) 0.70 22217
Brazil -0.63 (-0.63 – -0.62) 0.74 190555
Colombia -0.48 (-0.49 – -0.48) 0.63 38552
Ecuador -0.78 (-0.79 – -0.77) 0.85 8302
French Guiana -0.48 (-0.5 – -0.46) 0.63 3298
Guyana -0.25 (-0.26 – -0.23) 0.45 7372
Peru -0.68 (-0.69 – -0.68) 0.78 47363
Suriname -0.26 (-0.28 – -0.24) 0.46 5756
Venezuela -0.38 (-0.39 – -0.38) 0.56 30022
Total 353437

Summary by basin.

In the table below “Amazon” includes the Amazon Basin together with the Araguaia-Tocantins Basin in Brazil. “Coastal North” covers the Guianas and includes the Essequibo Basin. “Coastal South” includes part of Maranhão State in Brazil.

Basin population change River length Endangered (prop) River length (km)
Amazon -0.606 (-0.61 – -0.6) 0.72 280121
Coastal North -0.339 (-0.35 – -0.33) 0.52 20835
Coastal South -0.973 (-0.97 – -0.97) 1.00 6467
Orinoco -0.501 (-0.51 – -0.49) 0.64 46014

Summary by major basins and countries.

Basin Country population change River length Endangered (prop) river length (km)
Amazon Bolivia -0.58 (-0.58 – -0.57) 0.70 22217
Amazon Brazil -0.62 (-0.62 – -0.61) 0.73 180434
Amazon Colombia -0.35 (-0.36 – -0.34) 0.53 18687
Amazon Ecuador -0.78 (-0.79 – -0.77) 0.85 8302
Amazon Guyana -0.98 (-0.98 – -0.98) 1.00 423
Amazon Peru -0.68 (-0.69 – -0.68) 0.78 47363
Amazon Venezuela 0.07 (0.05 – 0.09) 0.22 2695
Coastal North Brazil -0.52 (-0.54 – -0.49) 0.66 3653
Coastal North French Guiana -0.48 (-0.5 – -0.46) 0.63 3297
Coastal North Guyana -0.2 (-0.22 – -0.19) 0.41 6928
Coastal North Suriname -0.26 (-0.28 – -0.24) 0.46 5756
Coastal North Venezuela -0.59 (-0.62 – -0.56) 0.72 1201
Coastal South Brazil -0.97 (-0.97 – -0.97) 1.00 6466
Orinoco Colombia -0.61 (-0.61 – -0.6) 0.72 19865
Orinoco Venezuela -0.42 (-0.43 – -0.41) 0.58 26126

The table values can also be presented graphically. This enables a more comprehensive understanding of the patterns.

Columns show predicted population changes for each basin country combination. The backgrouund shading follows a gradient from Near Threatened (-0.2 / 20% loss) to Critically Endangered (-0.8, 80% loss). The width of columns is proportional to the river length on a log scale (labels show river lengths in thousands of kilometers).

Next steps

  • Consultate with researchers to check and validate the mapped results.